Abstract
OBJECTIVE: Spondyloarthritides (SpA) and inflammatory bowel disease (IBD) are immune-mediated diseases with overlap in clinical and immunologic features. However, temporal correlation of SpA and IBD in individual patients and risk factors are not well characterized. METHODS: We conducted a nationwide population-based study between January 1, 1998, and July 31, 2022, to determine SpA prevalence preceding IBD diagnosis and its incidence following IBD diagnosis. Using cross-linked register data, we identified individuals with IBD diagnosis and matched them to individuals without IBD. Using logistic regression, we determined the odds of SpA preceding IBD diagnosis, and using Cox regression, we determined the hazard of new-onset SpA following IBD diagnosis. RESULTS: Of 102,648 individuals included in the study, 17,108 (16.7%) individuals were diagnosed with IBD. The adjusted odds ratios of SpA in the eight-year period preceding IBD, Crohn disease (CD), and ulcerative colitis (UC) diagnosis, compared to matched individuals, were 1.95 (95% confidence interval [CI] 1.78-2.14), 2.84 (95% CI 2.43-3.32), and 1.61 (95% CI 1.43-1.81), respectively. The adjusted hazard ratios of SpA following IBD, CD, and UC diagnosis, compared to matched individuals, were 2.51 (95% CI 2.34-2.70), 3.17 (95% CI 2.81-3.59), and 2.24 (95% CI 2.05-2.45), respectively. SpA prevalence demonstrated temporal variability, with an increase during the few years around IBD diagnosis. Associations were stronger for axial SpA and among women and young adults following IBD diagnosis. CONCLUSION: In a population-based cohort, we report that SpA diagnosis is associated with IBD preceding and following its diagnosis. We demonstrate temporal variability and highlight clinical variables associated with SpA in IBD.